THE CANADIAN FIELD-NATURALIST > 



VOL. XXXV. 



GARDENVALE, QUE., October-December, 1921. 



No. 7. 



A PRELIMINARY SURVEY OF THE BIOTA OF A SAND SPIT IN 

 LAKE WINNIPEG. 



By Chas. H. O'Donoghue, D.Sc, F.Z.S. 



Professor of Zoologj^, University of Manitoba. 



Early in July, 1918, I was enabled to 

 make a short stay of eight days on Berens 

 Island, Lake Winnipeor, through the court- 

 esy of the Riverton Fish Company of Ri- 

 verton, Man. I was aeeompanied by J. 

 Nelson Gowanloek, B.A., Fellow in Zoo- 

 logy in the University of Manitoba, and 

 we both desire to express our thanks to the 

 company for a round trip of some 500 miles 

 from Hnausa, taking in Berens Island, and 

 also to the men at the fishing camp at 

 Swampy Harbour for many favours. 



The main object of the trip was to be- 

 come acquainted with the general life con- 

 ditions in the great tree belt of the "Can- 

 adian zone" which occupies such a large 

 part of the Province of Manitoba. To 

 this end a camping site was chosen on 

 Berens Island which is situated well with- 

 in that region and, save for a small corner, 

 has not been interfered with by settle- 

 ment. Further, the journey there and 

 back allowed of short visits to a number 

 of typical and practically undisturbed 

 spots. 



Adams (1) points out that for satisfact- 

 ory ecological study only "repeated and 

 prolonged visits, careful observations, and 

 descriptions of the place and animals will 

 enable one to acquire the desired famili- 

 arity." This was obviously impossible in 

 a short stay, but the whole area was so 

 full of interest that it seemed highly desir- 

 able to call attention to its possibilities, 

 and, further, it was hoped that opportu- 

 nities would occur later to revisit the spot 

 or perhaps induce other people to do so 

 and continue the work in a more satis- 

 factory manner. This hope has not been 

 realised, and the present paper makes no 

 pretence at completeness but is intended to 

 serve as an introductory survey. 



The following notes relate particularly 

 to a sketch of the life conditions on a sand 



spit of Berens Island. Similar spits oc- 

 cur at other places on the lake, but, so 

 far as I know, none combine so fully two 

 important considerations, namely accessi- 

 bility and, at the same time, almost com- 

 plete freedom from human interference. 

 In Shelford's terms it is a "primeval or 

 primary community" (7). Press of work 

 has prevented their publication at an ear- 

 lier date. It is hoped, however, that they 

 will be of some interest and serve to call 

 attention, inter alia, to the fact that prac- 

 tically no ecological studies have been 

 carried out on the islands and shores of 

 freshwater lakes in Northern Canada 

 where the conditions differ greatly from 

 those farther south. 



Berens Island is one of the two large 

 islands in the northern part of Lake Win- 

 nipeg and lies approximately in latitude 

 52 deg. 15 min. N. and longitude 97 deg. 15 

 min. W. Its greatest length is eight miles 

 and its greatest Avidth four. The north-west 

 sandy shore stretches in a very shallow cur- 

 ve for about seven and a half miles and faces 

 the north-west corner of the lake which is 

 over 120 miles away. The remaining part 

 of the coast is more indented and rocky 

 and has a large rounded projection on the 

 south corner. As is well known the east- 

 ern and western shores of Lake Winnipeg 

 differ markedly in character owing to the 

 nature of the formation on which they lie. 

 The former is composed of the Laurentian 

 rocks, and the latter of Cambro-Silurian 

 and a certain amount of alluvial drift. Al- 

 though the island lies nearer the eastern 

 than the western shore, it is nevertheless 

 inside the limits of the Cambro-Silurian 

 but must lie very near the junction be- 

 tween the two. The island is well within 

 the limits of the Canadian zone and its 

 characteristic trees are the Spruce, Picea 

 mariana, and the Tamarack, Larix larioina, 



